awk's empty for(;;) condition evaluates as false, so the loop body never runs

[davydog187]

awk's empty for(;;) condition evaluates as false, so the loop body never runs.

$ awk 'BEGIN{n=0; for(;;){n++; if(n>3) break}; print n}'
0                 # gawk on the same machine prints 4

$ awk 'BEGIN{for(;;){x=x+1}}'
                  # exit 0, empty stderr, 0 ms

In awk, an omitted for condition means true — for(;;) is the idiomatic infinite loop, exited with
break. JustBash treats the missing condition as false and skips the body entirely, so any loop written
that way is silently a no-op and whatever it was meant to compute never happens.

Note the failure mode: exit 0, no diagnostic, wrong answer. for(;;) is common enough in awk one-liners
that an agent writing one gets a confidently wrong result.

The bounded variant is fine — for(i=0;i>=0;i++) runs and is correctly stopped by the wall clock at
~1002 ms — so this is specific to the empty-condition form, not to for generally. Check while() and
do-while for the same treatment of an absent or empty condition.

Likely in lib/just_bash/commands/awk/evaluator.ex around the for clause at :590.

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Pre-existing. Verified byte-identical at 16c85b3 and afe0aa8. It terminates, so it is a correctness
bug rather than a sandbox-termination hole, which is why it was left out of #69.

Found by an independent verification pass while working #69 (PR #73).